Soak beans in water , covered overnight. In a large Dutch oven, cook beef until browned, stirring to keep crumbly, Drain off drippings, if needed. Add tomato paste, onions and drained beans. Mix chili powder, cumin and season to taste with salt.Stir into mixture. Bring to boil, reduce heat, cover and simmer until beans are tender, about 5 hours. Serves 6